Fios TV was recently installed with a Motorola QIP6416-1 HD-DVR. I read the userguide online that mentions some user settings such as aspect ratio. I cannot access these settings.

Category:FiosTV FAQ

The aspect ratio (4:3 480i,16:9 1080i, etc.) is changeable via the 'Video Settings' sub menu that is accessible if you press [STB] and then [MENU]. Look for it under the 'Settings' menu item. If the display becomes distorted or does not display at all, the TV does not support the aspect ratio/display combination, and you can opt out by pressing the [OK] button, as this will revert to the previous settings.

It is also accessible via the internal menu that can be accessed by powering off the STB and pressing the SELECT button several times until the menu appears. When changing it there, however, the change is not immediately reversible like it is in the method above. If your display becomes distorted, you may have to make several other keypresses at the STB to reverse the change.